In the past year or so, I've almost completely switched over to card from styrene. If you choose the right subject, you can make a good-looking model, it's a lot cheaper and if you screw up a part, you just print out a new one.
There are some really talented builders working in card. In many ways, building in card offers more challenges than working in styrene, particularly for the scratchbuilder, since you're having to figure out how to build a three-dimensional object from a two-dimensional material.
I build mostly Real Space subjects, and for those who care, I've posted some photos in my album at www.cardmodels.net. The address is
http://www.cardmodels.net/phpbb2/album_personal.php?user_id=370.
If I can get around to it this weekend, I'll take and post some photos of my latest, a Delta IV Medium+(5,4) in 1/96th scale.